Long Feet Offer Clues to Mystery of Small Hominid
By JOHN NOBLE WILFORD
The extinct hominids commonly known as hobbits may have been small of
body and brain, but their feet were exceptionally long, and they were
flat.
Scientists, completing the first detailed analysis of the hominid’s
foot bones, say the findings bolster their controversial
interpretation that these individuals belonged to a primitive
population distinct from modern humans that lived as recently as
17,000 years ago on the Indonesian island of Flores.
The new anatomical evidence, being reported Thursday in the journal
Nature, is unlikely to solve the mystery of just where the species —
formally designated Homo floresiensis — fits in human evolution. That
fact even the researchers acknowledge, and some of their critics still
contend that the skull and bones are nothing more than remains of
modern pygmy humans deformed by genetic or pathological disorders.
The controversy erupted almost immediately after the H. floresiensis
discovery was announced in 2004. The single skull was unusually small,
indicating its brain was no bigger than a chimpanzee’s. It topped a
body little more than three feet tall.
Now the examination of lower limbs and especially an almost complete
left foot and parts of the right, the researchers reported, shows that
the species walked upright, like other known hominids. There were five
toes, as in other primates, but the big toe was stubby, more like a
chimp’s.
Stranger still was the size of the feet — more than seven and a half
inches long, out of proportion to its short lower limbs. The imbalance
evoked the physiology of some African apes, but it has never before
been seen in hominids.
And then there were those flat feet. Humans sometimes have fallen
arches and flat feet, but scientists noted that this was no human
foot. The navicular bone, which helps form the arch in the modern
foot, was especially primitive, more akin to one in great apes.
Without a strong arch — that is, flat-footed — the hominid would have
lacked the spring-like action needed for efficient running. It could
walk, but not run like humans.
Weighing the new evidence, the research team led by William L.
Jungers, a paleoanthropologist at the Stony Brook Medical Center on
Long Island, concluded that “the foot of H. floresiensis exhibits a
broad array of primitive features that are not seen in modern humans
of any body size.”
The team contended that it is improbable that all of these traits from
head to toe — including small brain and primitive shoulders and
wrists, as previously reported — “were simply a consequence of ‘island
dwarfing.’ ”
Dr. Jungers and his colleagues raised the possibility that the
ancestor of the species was not Homo erectus, as had been the original
assumption. H. erectus is known as the earliest hominid to leave
Africa and make its way across Asia. At a symposium two weeks ago,
several scientists edged toward the view that the so-called hobbits
emerged from another, more primitive hominid ancestor.
In a commentary accompanying the journal report, Daniel E. Lieberman,
a paleoanthropologist at Harvard University who was not a member of
the team, noted that the initial skepticism over the hominid as a
distinct species was understandable.
“All in all, many scientists (myself included) have sat on the fence,
waiting for more evidence about the nature and form of H.
floresiensis,” Dr. Lieberman wrote. “And now we have some.”
Dr. Lieberman, who specializes in hominid locomotion studies, said the
primitive foot provided a “tantalizing model” for a nonmodern hominid
that “evolved for effective walking before selection for endurance
running occurred in human evolution.”
That might have occurred even before H. erectus, judging by footprints
in Africa of an erectus with an apparently humanlike foot. Some
scientists speculate that the ancestor of H. floresiensis evolved from
an earlier and smaller erectus, or the enigmatic Homo habilis, or even
a pre-Homo genus.
In a related report in the journal, Eleanor Weston and other
researchers at the Natural History Museum in London suggested that the
H. floresiensis skull might be that of an erectus that had become
dwarfed from living isolated on an island. They made the proposal
based on a study of extinct dwarf hippos on Madagascar, whose brains
were 30 percent smaller than would be expected by scaling down their
mainland African ancestor.
Robert E. Eckhardt, an evolutionary biologist at Penn State University
who remains skeptical, said in an e-mail message that supporters of
that interpretation “have ignored, overlooked, discounted or
misrepresented the extent of normal and abnormal variation in
morphological structure and biomechanical function that exists in
members of our own species, Homo sapiens.”
William Harcourt-Smith, a paleoanthropologist at the American Museum
of Natural History and co-author of the Nature paper, said in an
interview, “We have been very careful to consider variables within a
species and possible pathologies, but this hobbit foot is another
strong piece of evidence that they were nothing like us.”
http://www.nytimes.com/2009/05/07/science/07hobbit.html?pagewanted=print
"Hobbit" Foot Like No Other In Human Fossil Record
Description
An international team of paleoanthropologists, anatomists and
archeologists, led by William L. Jungers, Ph.D., of Stony Brook
University,have published the first scientific analysis of the foot of
Homo floresiensis, the fossil found in Indonesia in 2003 and popularly
referred to as the “Hobbit.” Their findings are reported in the May 7
issue of Nature.
Image Gallery
Djuna Ivereigh/ARKENAS
Assembly of the "Hobbit" foot.
Click image to view fullsize
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Newswise — An international team of paleoanthropologists, anatomists
and archeologists have published the first scientific analysis of the
foot of Homo floresiensis, the fossil found in Indonesia in 2003 and
popularly referred to as the “Hobbit.” Lead author William L. Jungers,
Ph.D., of Stony Brook University, and colleagues documented the
Hobbit’s unusual combination of ape-like and human-like foot features,
which clearly enabled bipedal walking, a hallmark of all humans and
their extinct relatives (hominins), despite its surprisingly primitive
design. Their findings, reported in the May 7 issue of Nature, provide
further evidence that the ancestor of this species was perhaps not
Homo erectus but instead another more primitive and remote hominin.
The authors point out that the Hobbit foot has a relative foot length
that far exceeds the upper limits for modern humans either of average
or short stature. The foot is similar in relative length to pygmy
chimpanzees, with long and curved toes, but also sports a short big
toe in line with the other toes. While the foot has an overall
structure that signals bipedal walking, it appears to have been “flat-
footed” and poorly designed for running, one of the critical pedal
features believed to characterize human ancesters since the time of
Homo erectus.
“A foot like this one has never been seen before in the human fossil
record,” says Dr. Jungers, Distinguished Teaching Professor and Chair
of the Department of Anatomical Sciences at Stony Brook. “Our analysis
offers the most complete glimpse to date of how a primitive bipedal
foot was designed and differed from that of later hominins and modern
humans.”
“Arches are the hallmark of a modern human foot,” explains co-author
Dr. William E. H. Harcourt-Smith of the American Museum of Natural
History. “This is another strong piece of the evidence that the
‘hobbit’ was not like us.”
In “The foot of Homo floresiensis,” the authors also suggest that
despite these feet being dated to the Late Pleistocene age (17,000
years ago), their features together with many other parts of the Homo
floresiensis skeleton, might represent the primitive condition for our
own genus Homo. This could imply a dispersal event out of Africa
earlier than what paleoanthropologists have long thought.
“These particular ‘hobbit’ feet may have never walked into Mordor, but
they certainly remind us how little we know about which other hominin
species walked out of Africa and the many possible places their feet
helped take them,” adds co-author Dr. Matthew Tocheri, of the
Smithsonian Institution.
Dr. Jungers points out that “if the feet and skeleton of the ‘hobbits’
are instead the result of ‘island dwarfing’ from the Southeast Asian
Homo erectus as some scientists suspect, then an amazing number of
evolutionary reversals to primitive conditions had to occur as an
unexplained and unprecedented by-product.”
Continued excavations on Flores and other parts of Indonesia, to be
led by co-author Dr. Mike Morwood, of the University of Wollongong in
Australia, in collaboration with Indonesian scientists from the
National Research and Development Centre for Archeology in Jakarta,
may unearth an answer to the competing theories on the origins and
nature of Homo floresiensis.
The research for this international study was supported by grants from
the Australian Research Council, the National Geographic Society, the
Wenner-Gren Foundation for Antrhopological Research, the Wellcome
Trust and the Leakey Foundation.
In addition to Dr. Jungers, co-authors of the study include: W. E. H.
Harcout-Smith, Division of Paleontology, American Museum of Natural
History; R.E. Wunderlich, Department of Biological Sciences, James
Madison University; M.W. Tocheri, Department of Anthropology,
Smithsonian Institution; Susan G. Larson, Department of Anatomical
Sciences, Stony Brook University Medical Center; T. Sutikna and Rhokus
Awe Due, of the National Research and Development Centre for
Archeology, Jakarta, Indonesia, and M.J. Morwood, School of Earth and
Environmental Sciences, University of Wollongong, New South Wales,
Australia.
The Department of Anatomical Sciences is one of 25 departments within
Stony Brook University School of Medicine. The department includes
graduate and doctoral programs in Anatomical Sciences. Fields of study
include research on human evolutionary anatomy, morphology and
vertebrate paleontology. Many faculty members in the department are
also participants in an interdepartmental graduate program in
anthropological sciences that is recognized worldwide for its faculty
and research strengths in functional morphology and human evolution.
© 2009 Newswise. All Rights Reserved.
http://www.archaeologynews.org/story.asp?ID=434763&Title=
Letter
Nature 459, 85-88 (7 May 2009) | doi:10.1038/nature07922; Received 15
January 2008; Accepted 19 February 2009
Insular dwarfism in hippos and a model for brain size reduction in
Homo floresiensis
Eleanor M. Weston1 & Adrian M. Lister1
1. Department of Palaeontology, Natural History Museum, London SW7
5BD, UK
Correspondence to: Eleanor M. Weston1 Correspondence and requests for
materials should be addressed to E.W. (Email: e.wes...@nhm.ac.uk).
Abstract
Body size reduction in mammals is usually associated with only
moderate brain size reduction, because the brain and sensory organs
complete their growth before the rest of the body during ontogeny1, 2.
On this basis, 'phyletic dwarfs' are predicted to have a greater
relative brain size than 'phyletic giants'1, 3. However, this trend
has been questioned in the special case of dwarfism of mammals on
islands4. Here we show that the endocranial capacities of extinct
dwarf species of hippopotamus from Madagascar are up to 30% smaller
than those of a mainland African ancestor scaled to equivalent body
mass. These results show that brain size reduction is much greater
than predicted from an intraspecific 'late ontogenetic' model of
dwarfism in which brain size scales to body size with an exponent of
0.35. The nature of the proportional change or grade shift2, 5
observed here indicates that selective pressures on brain size are
potentially independent of those on body size. This study demonstrates
empirically that it is mechanistically possible for dwarf mammals on
islands to evolve significantly smaller brains than would be predicted
from a model of dwarfing based on the intraspecific scaling of the
mainland ancestor. Our findings challenge current understanding of
brain–body allometric relationships in mammals and suggest that the
process of dwarfism could in principle explain small brain size, a
factor relevant to the interpretation of the small-brained hominin
found on the Island of Flores, Indonesia6.
1. Department of Palaeontology, Natural History Museum, London SW7
5BD, UK
Correspondence to: Eleanor M. Weston1 Correspondence and requests for
materials should be addressed to E.W. (Email: e.wes...@nhm.ac.uk).
Letter
Nature 459, 81-84 (7 May 2009) | doi:10.1038/nature07989; Received 14
January 2009; Accepted 17 March 2009
The foot of Homo floresiensis
W. L. Jungers1, W. E. H. Harcourt-Smith2, R. E. Wunderlich3, M. W.
Tocheri4, S. G. Larson1, T. Sutikna5, Rhokus Awe Due5 & M. J. Morwood6
1. Department of Anatomical Sciences, Stony Brook University
Medical Center, Stony Brook, New York 11794-8081, USA
2. Division of Paleontology, American Museum of Natural History,
New York, New York 10024, USA
3. Department of Biological Sciences, James Madison University,
Harrisonburg, Virginia 22807, USA
4. Humans Origins Program, Department of Anthropology, National
Museum of Natural History, Smithsonian Institution, Washington DC
20013-7012, USA
5. National Research and Development Centre for Archaeology,
Jakarta 12001, Indonesia
6. School of Earth and Environmental Sciences, University of
Wollongong, Wollongong, New South Wales 2522, Australia
Correspondence to: W. L. Jungers1 Correspondence and requests for
materials should be addressed to W.L.J. (Email:
william.jung...@stonybrook.edu).
Top of page
Abstract
Homo floresiensis is an endemic hominin species that occupied Liang
Bua, a limestone cave on Flores in eastern Indonesia, during the Late
Pleistocene epoch1, 2. The skeleton of the type specimen (LB1) of H.
floresiensis includes a relatively complete left foot and parts of the
right foot3. These feet provide insights into the evolution of
bipedalism and, together with the rest of the skeleton, have
implications for hominin dispersal events into Asia. Here we show that
LB1's foot is exceptionally long relative to the femur and tibia,
proportions never before documented in hominins but seen in some
African apes. Although the metatarsal robusticity sequence is human-
like and the hallux is fully adducted, other intrinsic proportions and
pedal features are more ape-like. The postcranial anatomy of H.
floresiensis is that of a biped1, 2, 3, but the unique lower-limb
proportions and surprising combination of derived and primitive pedal
morphologies suggest kinematic and biomechanical differences from
modern human gait. Therefore, LB1 offers the most complete glimpse of
a bipedal hominin foot that lacks the full suite of derived features
characteristic of modern humans and whose mosaic design may be
primitive for the genus Homo. These new findings raise the possibility
that the ancestor of H. floresiensis was not Homo erectus but instead
some other, more primitive, hominin whose dispersal into southeast
Asia is still undocumented.
1. Department of Anatomical Sciences, Stony Brook University
Medical Center, Stony Brook, New York 11794-8081, USA
2. Division of Paleontology, American Museum of Natural History,
New York, New York 10024, USA
3. Department of Biological Sciences, James Madison University,
Harrisonburg, Virginia 22807, USA
4. Humans Origins Program, Department of Anthropology, National
Museum of Natural History, Smithsonian Institution, Washington DC
20013-7012, USA
5. National Research and Development Centre for Archaeology,
Jakarta 12001, Indonesia
6. School of Earth and Environmental Sciences, University of
Wollongong, Wollongong, New South Wales 2522, Australia
Correspondence to: W. L. Jungers1 Correspondence and requests for
materials should be addressed to W.L.J. (Email:
william.jung...@stonybrook.edu).
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